Electromechanical conversion systems

Electromechanical conversion has been a core theme of GREEN since its inception. The main thrust of this theme is the design and control of electromechanical conversion chains. It is no longer possible to make do with simplified models because, as devices reach their operating limits, second-order parasitic phenomena that were neglected or dealt with a posteriori (3D effect, heating, non-linearities, etc.) must be taken into account from the outset of the design. By definition, an electromechanical conversion system may comprise several components that we can classify in the following categories:

• Energy sources and/or storage,
• Power electronics combined with a control and monitoring strategy (reliability, diagnostics, ageing, etc.),
• Electromechanical converters,
• Accessories: non-contact torque transmission, non-contact battery charger, protective devices, cooling system, cryogenics, etc.

The first scientific issue concerns the so-called ‘internal’ modelling of devices governed by Partial Differential Equations (PDEs). Models of electrochemical devices combine the phenomena of material diffusion and charge transport in the electrodes and electrolyte with heat transfer.With regard to the design of electrical machines, our strategy is to develop our own models and analysis tools and to validate them on experimental benches.

The second scientific issue is based on the construction of so-called ’external’ models derived from ‘internal’ modelling and/or measurements. These models are written in the form of a system of Ordinary Derivative Equations (ODE) associated with measurable physical parameters, taking account of non-linearities, the multiphysical nature of the object and parameter drift. The aim is to use this type of knowledge model to manage and diagnose devices (state of charge, state of health, functional state of electrochemical devices, ageing, non-linear models for monitoring and controlling actuators, etc.) and also for optimal design.